US8250855B2 - Procedure for operating a reducing agent metering valve of a SCR-exhaust gas purifying system - Google Patents

Procedure for operating a reducing agent metering valve of a SCR-exhaust gas purifying system Download PDF

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US8250855B2
US8250855B2 US12/058,202 US5820208A US8250855B2 US 8250855 B2 US8250855 B2 US 8250855B2 US 5820208 A US5820208 A US 5820208A US 8250855 B2 US8250855 B2 US 8250855B2
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valve
solenoid
electric current
current
gradient
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US20090077949A1 (en
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Horst KLEINKNECHT
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • F01N2550/05—Systems for adding substances into exhaust
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/10—Adding substances to exhaust gases the substance being heated, e.g. by heating tank or supply line of the added substance
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1486—Means to prevent the substance from freezing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Definitions

  • the invention is based on a procedure according to the genus of claim 1 .
  • Reducing agent metering valves that are electromagnetically controllable present a solenoid, whose magnetic field lifts off a pintle from a seal seat at a sufficiently high solenoid current so that the reducing agent metering valve opens.
  • a first sector of a current profile is that the reducing agent metering valve is opened quickly and the function of a second sector is to keep the already opened valve open with a small average amperage in order to control a flow of reducing agent.
  • Such a procedure as well as such a controller are known for an application in motor vehicles like automobiles and trucks from the publication Diesel motor-Management, 4th Edition, Friedrich Vieweg und Sohn Publishers, ISBN 3-528-23873-9, p. 338.
  • the selective reduction of nitrous oxides is based on a reduction of nitrous oxides (NOx) by selected reducing agents even in the presence of oxygen.
  • Selective means at this, that the oxidation of the reducing agent takes preferably place (selectively) with the oxygen of the nitrous oxides and not with the molecular oxygen that is essentially abundant in the exhaust gas.
  • Ammoniac (NH3) has approved itself as reducing agent with the highest selectiveness. In motor vehicles ammoniac is not carried along in pure form, but dosed to the exhaust gas from a urea-water-solution that has been carried along. Urea (NH2)2CO shows a very good solubility in water and can therefore be simply dosed to the exhaust gas.
  • a reducing agent in this application, this term shall also describe the primary products, the vehicles and media like water, in which a vehicle or the reducing agent is contained in dissolved form. Therefore also the urea-water-solution is described in the following as reducing agent that has to be dosed.
  • a urea-water-solution with a mass concentration of 32.5% urea which is known under the trade name AdBlue, has a freezing point at ⁇ 11 C.
  • a eutectic mixture establishes there, whereby an unmixing of the solution is excluded in the case of a freezing.
  • the reducing agent metering valve is generally provided with a cooling element, which allows a deduction of big heat quantity to the environment.
  • the cooling element increases the risk of a freezing of the reducing agent metering valve and aggravates the defrosting of a frozen reducing agent metering valve.
  • the task of the invention is to prevent a freezing of a reducing agent metering valve and/or to allow a defrosting of such a reducing agent metering valve with means as simple as possible, with costs as low as possible and with an operating safety as high as possible.
  • the checking that takes place in the first sector allows a differentiation of operating statuses without a danger of freezing and such with a danger of freezing. Thereby a heating effect can also be minimized in operating statuses without a danger of freezing, which decreases the danger of an overheating at a hot exhaust gas system and exhaust gas.
  • a special advantage is also that the heating effect takes place by modifying current profiles, as they are created for a percolation controlling anyways.
  • By the limitation to such current profiles the danger of an involuntary dosage of reducing agent is minimized.
  • An involuntary dosage could for example occur if a current flow is created by the solenoid with an intended opening of the valve, since each solenoid current creates an electromagnetic force action on to the movable seal body of the valve.
  • the effective locking force resulting from electromagnetic force action and mechanically created restoring force
  • the drop of reducing agent related to this shortens the time until the next refilling of reducing agent, which is undesirable. Furthermore the involuntary opening can cause that the reducing agent does not react with nitrous oxides, but gets into the environment while releasing ammoniac, which could cause odor nuisance.
  • FIG. 1 the technical surrounding of the invention
  • FIG. 2 mechanic and hydraulic details of the reducing agent metering valve
  • FIG. 3 the interaction of mechanic and electric features of the reducing agent metering valve
  • FIG. 4 a current profile which controls the reducing agent metering valve
  • FIG. 5 an electric equivalent circuit diagram of the reducing agent metering valve
  • FIG. 6 an amperage course, in which the opening of the valve is illustrated
  • FIG. 7 an embodiment which is based on an analysis of temporal behavior of a reducing agent pressure.
  • FIG. 1 shows a combustion engine 10 with a controller 14 .
  • the controller 14 is preferably the controller, which controls the combustion engine 10 and therefore receives signals from the sensors 16 about operating parameters of the combustion engine and processes them to correcting variables for controlling elements 18 of the combustion engine 10 .
  • the signals of the sensors 16 typically allow the controller 14 to determine the air mass that has been sucked in by the combustion engine 10 , the rotation angle positioning of a crankshaft of the combustion engine 10 and the temperature of the combustion engine 10 etc. From these signals the controller 14 typically creates correcting variables for dosing fuel into combustion chambers of the combustion engine, for adjusting a manifold pressure of an exhaust gas turbocharger, an exhaust gas recirculation rate etc.
  • controller 14 is a separate controller, which communicates with the controller of the combustion engine 10 over a bus system.
  • the controller 14 is arranged, particularly programmed, to implement the procedure according to the invention and/or one of its embodiments that are described in the following, which means to control the process of the procedure in each case and to implement the therefore necessary analyses.
  • the exhaust gas system 12 shows an oxidation catalyzer 20 and a SCR-catalyzer 22 .
  • a valve 24 is arranged between the oxidation catalyzer 20 and the SCR-catalyzer 24 , by which the reducing agent 26 is dosed from a reservoir 28 to the exhaust gas.
  • the valve 24 is electromagnetically operated and therefore controlled by the controller 12 with a control current I, which flows through a solenoid of the valve 24 . Thereby the supply of the valve 24 with reducing agent 26 takes place over a feed line 30 , which is fed with the reducing agent 26 by a pump 32 .
  • the pump 32 is preferably used as a controllable suction- and pressure-pump, which creates the injection pressure during pressure operation that is required for dosing of reducing agent 26 to the exhaust gas system 12 and which allows an emptying of reducing agent 26 from the feed line 30 during suction operation. Therefore the pump 32 is also controlled by the controller 14 .
  • Such an emptying takes for example place between two driving cycles, or rather at the end of a driving cycle in order to prevent a temporal freezing of the reducing agent 26 in the feed line 30 , which is mostly implemented as a hose line, and in the valve 24 .
  • the feed line 30 is furthermore equipped with a hose line 34 , which is also controlled by the controller 14 .
  • a further heating is arranged in the reservoir 28 , which is also controlled by the controller 14 .
  • a pressure sensor 36 detects a reducing agent pressure that has been created by the pump 32 before the valve 24 .
  • the dotted line 37 represents the vehicle underbody. The components that are arranged below the line 37 , especially the feed line 30 and the valve 24 , are directly exposed to the ambient temperature and the air stream and can therefore freeze.
  • FIG. 1 shows therefore especially the technical surrounding, in which the invention is used.
  • the invention is not limited to the configuration of combustion engine 10 with an exhaust gas system 12 and the depicted sensors 16 , 36 and controlling elements 18 , 24 , 34 as shown in FIG. 1 .
  • alternative embodiments can show several sensors, which detect operating parameters of the exhaust gas system 13 and provide the controller 14 with corresponding measured data.
  • sensors are temperature sensors and/or sensors for detecting the NOx concentration in the exhaust gas before and/or after the SCR-catalyzer 22 and/or a sensor, which detects the ammoniac concentration in the exhaust gas after the SCR-catalyzer 22 and thereby allows the detection of an overdosing of reducing agent 26 .
  • FIG. 2 shows mechanic and hydraulic details of the valve 24 .
  • the valve 24 shows a valve body 38 , which is strongly attached to the exhaust gas system 12 .
  • a seal body 40 for example a pintle, axially movable arranged, which is pressed by locking forces onto a valve seat 42 , lifted by opening forces from the valve seat 42 and thereby releases a percolation profile 44 , by which reducing agent 26 is dosed into the exhaust gas system 12 .
  • FIG. 3 shows the interaction of mechanic and electric features of the valve 24 .
  • the valve 24 shows a solenoid 46 with an iron core 48 .
  • the movable seal body 40 is pressed by a spring 50 away from the iron core 48 onto the valve seat 42 , so that an air gap 52 emerges between the iron core 48 and the movable seal body 40 .
  • the solenoid 46 is connected by a switch 54 to an electrical source of energy 56 , which provides a voltage U.
  • the switch 54 creates furthermore with the electric source of energy 56 a final stage, which is integrated into the controller 14 .
  • the switch 54 of the final stage is controlled by a control block 58 , which represents the development of control signals, especially current profiles for the solenoid 46 .
  • the triggering takes especially place depending on the signal of a voltmeter 60 , which detects a voltage U over the solenoid 46 , and depending on the signal of an ammeter 62 , which detects the amperage of a solenoid current or a control current I. If the switch 54 is closed, the solenoid 46 is fed with the current I and creates thereby an electromagnetic opening force, which pulls the movable seal body 40 into the air gap 52 and thus lifts from its valve seat 42 .
  • FIG. 4 shows an embodiment of a current profile 64 , with which the valve 24 is controlled and which shows two consecutive sectors 66 and 68 .
  • the horizontally dotted line marks a current level 70 , which is necessary for the opening and keeping open of the valve 24 .
  • the current I is adjusted by the solenoid 46 of the valve 24 to a first comparably high value I 1 , in order to open the valve 24 quickly.
  • a low current I 2 is adjusted. But the low current I 2 processes still above the dotted line, which marks a holding current level 70 .
  • valve 24 is opened and kept open with the current profile 64 by the sum dt 3 of the times dt 1 and dt 2 . If a danger of freezing exists or the valve 24 shall be defrosted, the electric energy that has been fed into the solenoid 46 by the electric current I is increased. This can takes place by extending the second sector 68 and/or by increasing the amperage I 2 in the second sector 68 onto a value I 3 .
  • FIG. 5 shows an electric equivalent circuit diagram of the valve 24 together with the final stage of the controller 14 .
  • the solenoid 46 is shown as series connection of a pure inductance 72 and an Ohm resistance 74 .
  • a connection of a source of direct current voltage as source of electric energy 56 and a connection of the solenoid 46 of the valve 24 are each connected to a reference potential 74 , for example a controller mass.
  • the complementary connections of the solenoid 46 and of the source of direct current voltage that serves as source of energy 56 are connected with and separated from each other by the switch 54 .
  • the current profile 64 from FIG. 4 is created by the composition with the equivalent circuit diagram of FIG. 5 by a corresponding controlling of the switch 54 .
  • the current level I 1 which is adjusted in the first sector 66 , follows for example from the fact that the switch 54 is closed as long as the induction voltage of the inductance 72 after a closing of the switch 54 is so faded away that the entire or almost entire direct current voltage of the source of direct current voltage 56 adjusts over the solenoid 46 .
  • the direct current voltage that has been provided by the source of direct current voltage 56 is preferably higher than a threshold voltage, at which a not frozen valve 24 opens.
  • the current level I 2 in the second sector 68 arises on the other side from the fact that the switch 54 is alternatively closed (current ramp) and opened (current drop) if the induction voltage has still not faded away.
  • a release of Joule heat goes with each current flow through the solenoid 46 of the valve 24 due to the Ohm resistance 74 .
  • the valve 24 is controlled by the current profile 64 , in order to dose the reducing agent, the release of heat can be disruptive. This is especially the case, if the dosing takes place at a hot exhaust gas system 12 and hot exhaust gas, because then the danger of a thermal damage of the valve 24 , for example by overheating the solenoid, exists.
  • the decreasing of the amperage from value I 2 to value I 2 which is still sufficient for opening the valve 24 , decreases in this case the heat, which is released by the current I due to the Ohm resistance 74 of the solenoid 46 .
  • the release of Joule heat in the Ohm resistance 74 is used for a desired heating of the valve 24 .
  • the so determined temperature T(R) is compared to a preset threshold T_S, which separates temperature areas with and without a danger of freezing from each other. If T(R) is higher than the threshold T_S, the valve 24 is operated without specific heating measures by the current profile 64 and the holding current I 2 from FIG. 4 . If the temperature T(R) is on the other side lower than the threshold T_S, an operating of the valve 24 with an increased current level 13 takes place in the second sector 68 . As a result an energy is set, which has been fed into the solenoid 46 in the second sector 68 with the electric current I depending on whether the valve 24 is frozen or a danger of freezing exists. Thereby more electric energy is fed in at a low electric resistance (low temperature) than at high electric resistance (high temperature).
  • the area between the current level 12 and 13 in FIG. 4 represents a measure for the additionally spent electric energy, which is converted in the solenoid 46 into Joule heating warmth.
  • the increasing of the effective value (Root Mean Square-Value) of the solenoid current can cause a warming, while one can lower the value of the solenoid temperature by decreasing the effective value.
  • This is used in one embodiment to regulate the solenoid temperature to a preset nominal value, which lies in the temperature area without a danger of freezing and at which no danger of an overheating of the solenoid exists.
  • a minimal solenoid current is therefore provided as lower barrier for the solenoid current, which is so determined that the valve 24 still stays open at the minimal value of the solenoid current.
  • a further embodiment provides that a course of the gradient of the amperage is detected and evaluated for the analysis of the behavior of the electric current I.
  • FIG. 6 shows qualitatively such a course 77 , in which a movement of the movable seal body 40 is illustrated. If the valve 24 is closed, the current I raises initially from a point of time t 0 with a first gradient m 1 . At the point of time t 1 the seal body 40 lifts from its valve seat 42 and moves to an end stop, which it reaches at a point of time t 2 .
  • the curve 78 shows the distance s of the seal body 40 over the time schematically, whereby the lower level 80 represents the position at a closed valve 24 as first percolation profile and the upper level 82 the position of the seal body 40 at a completely opened valve 24 as a second percolation profile.
  • the movement of the seal body 40 is mapped between the point of time t 1 and t 2 in a flatter gradient m 2 of the current course 77 , which lies between a higher starting gradient m 1 and a higher further gradient m 3 .
  • the values of the gradients m 1 and m 3 are different, since they occur at different positions of the seal body 40 and thereby at different expansions of the air gap 52 .
  • one embodiment of the procedure provides that it is checked for the analysis of the behavior of the electric current I whether the course of the gradient shows a fist gradient m 1 , which adjusts at a first percolation profile, and a further gradient m 3 , which adjusts at a second percolation profile.
  • the fed-in electric energy is set to a lower value during further activations, if the course of the current shows the first gradient m 1 and the further gradient m 3 .
  • the occurrence of the first gradient m 1 and of the further gradient m 3 after further, repeated triggerings shows in particular that the initially blocked seal body 40 comes loose.
  • An alternative embodiment provides that it is checked for the evaluation of the behavior of the electric current I whether the course 77 of the gradient shows an inflexion point 84 , which is typical for a moving seal body 40 .
  • the heating effect is increased, if no inflexion 84 is shown, because this indicates a frozen valve 24 . If the course 77 however shows an inflexion point 84 , an operating of the valve 24 takes place with a non-increased heating effect.
  • Gradients m 1 , m 2 and m 3 arise from the fact that the change of positioning of the seal body 40 causes a change of the geometry of the air gap 52 in FIG. 3 and thereby a change of the correlation of the magnetic field and solenoid current I.
  • the valve 24 is closed and the air gap 52 is present at the point of time t 0 in FIG. 6 .
  • valve 24 is preferably controlled with an extended control time (extended second sector 68 ). Thereby the control is repeated until a movement of the seal body 40 is illustrated in the current course 77 .
  • extended control time extended second sector 68
  • the valve 24 is heated up over the entry of electric energy and the solenoid 46 . It is important that during the triggering a determination of the temperature, for example over the inner resistance R of the solenoid 46 , takes place, in order to prevent an overheating of the solenoid 46 if the valve 24 is still not fully defrosted. Due to this embodiment it can be realized, whether the seal body 40 is moving under the influence of the triggering with a current profile. But it cannot be determined whether the reducing agent 26 outside the valve 24 , for example in the feed line 30 , is still frozen.
  • FIG. 7 illustrates a further embodiment, which is based on an analysis of a temporal course of a pressure p of the reducing agent 26 in the feed line 30 during a triggering of the valve 24 .
  • the pressure p is detected in an embodiment with the pressure sensor 36 from FIG. 1 .
  • a pressure p of about 5 bar is created in the feed line 30 before the valve 24 by a pump 32 in one embodiment.
  • the valve 24 opens due to a triggering with the current profile 92 , the opening is only shown in the pressure course p(t) by a vibration process 94 . But this is only the case if the reducing agent 26 is liquid also outside the valve 24 .
  • This embodiment allows therefore a more complete checking than the analysis of the current course, with which the flexibility of the seal body 40 in the valve 24 can only be determined.
  • valve 24 is triggered by a current profile 86 on the other side and this triggering is not shown in a temporal pressure breaking at the triggering, further triggerings 88 , 90 take repeatedly place, at which each second sector of the current profile is extended (shown dotted), in order to heat the solenoid 46 and the frozen reducing agent in valve 24 .
  • the extension of individual current profiles 86 , 88 , 90 can not be to big, since temporally slow opening processes are not shown in the pressure course.
  • the pressure change is in particular only shown in a form that can be evaluated, if the short-term pressure drop takes comparably prompt place during a triggering.
  • This embodiment can be implemented both during the pressure build-up (filling of the feed line 30 ), during filled feed line 30 and during pressure drop (emptying of the feed line 30 ). It is also important here, that in the period of the triggering a checking of the temperature of the valve 24 takes place, in order to prevent an overheating of the solenoid 46 . With the embodiment of the pressure analysis it can be realized, whether the reducing agent metering system is frozen or free. Problems can occur, when no pressure drop is realized during a triggering and the missing pressure drop is conditioned by a leak in the system. It is therefore an advantage that the checking of the pressure course is combined with a density checking of the reducing agent metering system.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Magnetically Actuated Valves (AREA)
US12/058,202 2007-04-03 2008-03-28 Procedure for operating a reducing agent metering valve of a SCR-exhaust gas purifying system Expired - Fee Related US8250855B2 (en)

Applications Claiming Priority (3)

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DE102007017459 2007-04-03
DE102007017459.6 2007-04-03
DE102007017459.6A DE102007017459B4 (de) 2007-04-03 2007-04-03 Verfahren zur Dosierung von Reduktionsmittel zum Abgas eines Verbrennungsmotors und Steuergerät

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US9140165B2 (en) 2010-04-01 2015-09-22 Emitec Gesellschaft Fuer Emissionstechnologie Mbh Method for operating a delivery unit for a reducing agent and motor vehicle having a delivery unit
US9567989B2 (en) 2011-10-21 2017-02-14 Emitec Gesellschaft Fuer Emissionstechnologie Mbh Method for operating a feed pump operating in a pulsating manner and motor vehicle having a feed pump
US10240595B2 (en) 2012-12-07 2019-03-26 Emitec Gesellschaft Fuer Emissionstechnologie Mbh Method for emptying a device for providing a liquid additive
US11183698B2 (en) 2017-07-14 2021-11-23 Elringklinger Ag Fuel cell device and method for operating a fuel cell device

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FR2921105A1 (fr) * 2007-09-14 2009-03-20 Inergy Automotive Systems Res Systeme scr et methode pour sa purge
JP5326461B2 (ja) * 2008-09-22 2013-10-30 マツダ株式会社 エンジンの排気浄化装置
DE102008056860A1 (de) * 2008-11-12 2010-05-20 Bayerische Motoren Werke Aktiengesellschaft Verfahren zur selektiven katalytischen Reduktion von Stickoxiden im Abgas von Brennkraftmaschinen
US9797288B2 (en) * 2010-07-08 2017-10-24 GM Global Technology Operations LLC Method of operating a vehicle under frozen diesel emission fluid conditions
DE102010038394A1 (de) * 2010-07-26 2012-01-26 Robert Bosch Gmbh Verfahren zur Dosierung eines Reagenzmittels in einen Abgaskanal und Vorrichtung zur Durchführung des Verfahrens
DE102011082397B4 (de) 2011-09-09 2024-02-01 Robert Bosch Gmbh Verfahren zur Überwachung eines Dosierventils in einem SCR-Katalysatorsystem
DE102011088712B4 (de) 2011-12-15 2024-05-23 Robert Bosch Gmbh Verfahren zum Beheizen eines Fördermoduls in einem SCR-Katalysatorsystem
JP2013221425A (ja) * 2012-04-13 2013-10-28 Denso Corp 排気浄化装置のインジェクタ制御装置
DE102013212139B3 (de) * 2013-06-25 2014-01-16 Robert Bosch Gmbh Verfahren zum Lösen einer Klemmung eines Dosierventils, Vorrichtung zur Durchführung des Verfahrens, Steuergerät-Programm und Steuergerät-Programmprodukt
JP6274698B2 (ja) * 2014-10-23 2018-02-07 ボッシュ株式会社 還元剤噴射装置の制御装置及び制御方法並びに還元剤噴射装置
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DE102007017459A1 (de) 2008-10-09

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